nathan p5 and graham white valve

Ive learned a lot on this forum and would prefer buying from a member here rather than a stranger on eBay or craigslist. Ive had my shocker horns from hornblasters for 5 years now and want to upgrade to some p5’s. Just got a 7 gallon tank and will be buying another compressor soon along with some 5/8 line and a graham white valve for the system. Ever since I was a kid I would honk my godfathers p5’s and have grown up loving the sound of them and think it’s time for a set of my own. Don’t mind if they are dirty or need to be rebuilt. Would actually prefer them needing a little work so I could get them a little cheaper. Thank you for your time, -Travis